According to the applicant of the present invention, a luminaire is suggested in which a luminaire main body includes a lamp device which uses a GX 53 type cap standardized by an IEC (International Electrotechnical Commission) and has a light emitting diode as the light source, and a socket device for the GX 53 type cap on which the lamp device is detachably mounted (refer to PTL 1). The luminaire includes a cap portion of the lamp device which is held to the socket device, and a pressing body which presses the luminaire main body being a radiator in a contact direction.